Liver failure in patients with hepatic cirrhosis and portal hypertension is the most common cause of death following various types of portasystemic shunt. Both hemodynamic and metabolic factors are apparently of great importance in the pathogenesis of liver failure. Recently, Warren et al. have demonstrated metabolic superiority of selective shunting which results in maintenance of urea synthesis in the post-shunt liver. The relationship between pre-operative portal vein blood flow and total hepatic blood flow and the clinical response to a given portasystemic shunt is not understood because of the previous lack of appropriate techniques of total hepatic blood flow determination of cirrhotic patients. Using techniques which have been developed and applied in our institution, pre and post-shunt portal vein blood flow determination in non-anesthetized patients by direct methods is feasible. The effect of distal splenorenal or mesocaval shunt on major hemodynamic parameters is being studied. Post-shunt changes in hepatic metabolism are being investigated in response to both forms of portal decompression in view of the recently demonstrated metabolic superiority of the selective distal, selective shunts. The relationship of pre-operative and post-operative portal vein blood flow to post-operative morbidity, liver failure and mortality is being studied in patients randomized into groups in which either mesocaval or (Drapanas) interposition or selective distal splenorenal (Warren) shunt is performed. Clinical data, at this time, shows less hepatic encephalopathy in patients in whom distal splenorenal shunt has been performed as compared to encephalopathy in those patients in whom mesocaval shunt was performed. The hemodynamic data currently show a greater reduction in portal vein blood flow following mesocaval shunt as compared to distal splenorenal shunt. Carbohydrate, lipid and ammonia metabolism in cirrhosis and after portasystemic shunt are under investigation.